Conserving the head of Athena

The head of a marble statuette of Athena. Ince Blundell Collection, accession number 59.148.11

Hans Thompson, studying Conservation at the City and Guilds of London Art School, spent four weeks as an intern with sculpture conservation. Here he describes his project.

Introduction

The statuette of Athena from the Ince Blundell collection arrived in the workshop in three main sections. The head was detached from the body and the head itself had been broken in two. On closer inspection it was clear that large scale restorations had been carried out on the piece previously, most probably during the 18th Century when the piece was purchased by Henry Blundell. At this time it was the fashion, and therefore common practice, to unite two unrelated pieces of ancient sculpture into one whole statue by carving new sections that were missing. This is exactly the case here where the head and torso, both unrelated to one another, have been merged by 18th century carving that creates a complete statuette by adding arms and legs. Unfortunately, these types of restorations often included the insertion of iron dowels or pins to secure the new sections, which corrode when exposed to water and lead to cracking of the marble.

Analysis using X-radiography

The first step was to therefore assess whether there were any of these corroded dowels in the sculpture which could jeopardise the future of Athena. X-ray analysis was performed on the crest area of the Corinthian helmet where it was suspected dowels had been used, due to supposed red iron stains in the area; a significant indicator of corrosion product, Iron Oxide, leaching into the marble. The results of the analysis were staggering, producing an image that clearly showed two iron pins deep within the marble and confirming the width of the join between the restoration section and original classical section. Click on the thumbnails below to see the crest being prepared for X-radiography, and the results of the analysis.

Removal of the iron pins

This finding confirmed that the next step of the treatment was to remove these pins. This was achieved by using very fine dental tools to carefully scrape out the 18th century adhesive, a pine tree resin called Colophony.

Eventually, having followed the join line completely around the crest, wedges were used to carefully lift the crest away from the helmet and eventually completely separate the two. This exposed the iron dowels, both severely corroded, which were then carefully excavated from their holes. All resin was removed and all join surfaces cleaned thoroughly ready to be re-adhered.

Consolidation

The whole process was complicated by the fact that the original classical marble, called Parian marble, was extremely unstable; the structural integrity resembling something like that of a sugar cube in some areas. This meant that consolidation was necessary every step of the way to reinforce these weaknesses and stop the original material vanishing onto the workshop floor. When the restoration was eventually separated the whole front of the crest, original to the helmet, was faced with tissue to provide further support and solidity.

Reassembly

The pieces were then all reassembled using Perspex or stainless steel dowels that would not cause the same problems of corrosion in the future. The final process was to fill all the cracks and join lines to enable the sculpture to read without interruption.